Software-defined networking (SDN) allows network administrators to manage network services through abstraction of lower level functionality. This is done by decoupling the system that makes decisions about where traffic is sent (the control plane) from the underlying systems that forward traffic to the selected destination (the data plane).
There can be multiple types of virtual networks provided by a single service provider. One type of virtual network is a single customer single session service. Another type of virtual network is a bundle of services belonging to a group of users, such as a virtual network operated by a virtual network operator.